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Cardiology Research and Practice
Volume 2016 (2016), Article ID 4097471, 9 pages
http://dx.doi.org/10.1155/2016/4097471
Clinical Study

The Modification Effect of Influenza Vaccine on Prognostic Indicators for Cardiovascular Events after Acute Coronary Syndrome: Observations from an Influenza Vaccination Trial

1Ph.D. Program in Clinical Epidemiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
2Department of Pharmacy Practice, School of Pharmaceutical Sciences, University of Phayao, Phayao 56000, Thailand
3Cardiology Division, Department of Internal Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
4Social and Administrative Pharmacy Excellence Research (SAPER) Unit, Department of Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand
5Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand

Received 9 March 2016; Accepted 29 March 2016

Academic Editor: Mariantonietta Cicoira

Copyright © 2016 Apirak Sribhutorn et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Introduction. The prognosis of acute coronary syndrome (ACS) patients has been improved with several treatments such as antithrombotics, beta-blockers, and angiotensin-converting enzyme inhibitors (ACEI) as well as coronary revascularization. Influenza vaccination has been shown to reduce adverse outcomes in ACS, but no information exists regarding the interaction of other treatments. Methods. This study included 439 ACS patients from Phrommintikul et al. A single dose of inactivated influenza vaccine was given by intramuscular injection in the vaccination group. The cardiovascular outcomes were described as major cardiovascular events (MACEs) which included mortality, hospitalization due to ACS, and hospitalization due to heart failure (HF). The stratified and multivariable Cox’s regression analysis was performed. Results. The stratified Cox’s analysis by influenza vaccination for each cardiovascular outcome and discrimination of hazard ratios showed that beta-blockers had an interaction with influenza vaccination. Moreover, the multivariable hazard ratios disclosed that influenza vaccine is associated with a significant reduction of hospitalization due to HF in patients who received beta-blockers (HR = 0.05, 95% CI = 0.004–0.71, ), after being adjusted for prognostic indicators (sex, dyslipidemia, serum creatinine, and left ventricular ejection fraction). Conclusions. The influenza vaccine was shown to significantly modify the effect of beta-blockers in ACS patients and to reduce the hospitalization due to HF. However, further study of a larger population and benefits to HF patients should be investigated.